According to one embodiment, a method of acquiring rotational information of a gyro sensor includes sensing a predetermined physical quantity which depends upon an amplitude of a vibration in a second direction, the vibration in the second direction being based on Coriolis force that is applied to a movable body which is vibrating in a first direction, calculating rotational information of the movable body based on the sensed predetermined physical quantity, and stopping a vibration in the first direction of the movable body after the predetermined physical quantity is sensed.